Click here to Skip to main content
13,704,523 members
Click here to Skip to main content
Add your own
alternative version


18 bookmarked
Posted 7 Sep 2010
Licenced CPOL

32-Bit or 64-bit OS ??

, 21 Sep 2010
Rate this:
Please Sign up or sign in to vote.
A simple way to detect bitness of an OS Programatically. (C# and C++ examples given)
There's always been a fight over an optimal way to detect bitness of an OS. Most of the time, getting system information is considered to be solved using interop services or P/Invoke. For this, the methodology followed is as shown below:

public enum Platform

    internal const ushort PROCESSOR_ARCHITECTURE_INTEL = 0;
    internal const ushort PROCESSOR_ARCHITECTURE_IA64 = 6;
    internal const ushort PROCESSOR_ARCHITECTURE_AMD64 = 9;
    internal const ushort PROCESSOR_ARCHITECTURE_UNKNOWN = 0xFFFF;

    internal struct SYSTEM_INFO
      public ushort wProcessorArchitecture;
      public ushort wReserved;
      public uint dwPageSize;
      public IntPtr lpMinimumApplicationAddress;
      public IntPtr lpMaximumApplicationAddress;
      public UIntPtr dwActiveProcessorMask;
      public uint dwNumberOfProcessors;
      public uint dwProcessorType;
      public uint dwAllocationGranularity;
      public ushort wProcessorLevel;
      public ushort wProcessorRevision;

    internal static extern void GetNativeSystemInfo(ref SYSTEM_INFO lpSystemInfo);

    internal static extern void GetSystemInfo(ref SYSTEM_INFO lpSystemInfo);

    public static Platform GetPlatform()
      SYSTEM_INFO sysInfo = new SYSTEM_INFO();

      if(System.Environment.OSVersion.Version.Major > 5 ||
    (System.Environment.OSVersion.Version.Major == 5 && System.Environment.OSVersion.Version.Minor >= 1))
         GetNativeSystemInfo(ref sysInfo);
         GetSystemInfo(ref sysInfo);

      return Platform.X64;

      return Platform.X86;

      return Platform.Unknown;

Actually there's a simple way to do that in C#. C# provides a very useful struct IntPtr.

64-Bit Vs 32-Bit w.r.t Pointer

We all know that the size of an Pointer on a 32-bit machine compiled program is 4-Bytes. The size changes on a 64-Bit compiled program and becomes 8-bytes. Then why not compare the size of Integer. Pointer is nothing but an Integer and IntPtr serves the same for us in C#.

The following example shows the simple usage of IntPtr.
(UPDATE: As Win64 follows LLP64 Model (For more informarion on LLP64 model please follow Technet Article[^]) as corrected by codeproject member Ajay Vijayvargiya[^])

if(IntPtr.size == 4)
   //Your logic for 32-Bit.
  // Your logic for 64-Bit.

Previous code checks whether the program is running in 32-bit or 64-bit mode. This doesn't inform OS bitness.

If using C++/Win32:
IntPtr is not available in C++. Rather sizeof(int) does the same.

BOOL Is64BitOS()
	BOOL bIs64Bit = FALSE;

	#if defined(_WIN64)

	bIs64Bit = TRUE;  // 64-bit programs run only on Win64

	#elif defined(_WIN32)

	// Note that 32-bit programs run on both 32-bit and 64-bit Windows

	LPFNISWOW64PROCESS pfnIsWow64Process = (LPFNISWOW64PROCESS)GetProcAddress(GetModuleHandle(_T("kernel32")), "IsWow64Process");

	if (pfnIsWow64Process)
		pfnIsWow64Process(GetCurrentProcess(), &bIs64Bit);


	return bIs64Bit;

There's one more distinctive feature a 64-Bit OS supports: "Virtualization".

Virtualization (Windows Vista and 7 x64 Platform only)

Virtualization technologies are used by Windows Vista and 7 x64 platform only. These act like virtual machines just like VMWare or similar apps. The advantage here is to run legacy apps such s 32-bit apps. Running 32-Bit apps on 64-Bit OS becomes difficult without virtualization as such applications are usually not written to co-exist within a single execution environment.

64-Bit applications are never run virtualized, nor do 32 or 64-Bit services and drivers. Virtualization becomes active when running legacy 32-bit interactive apps under WOW64.

So if the OS supports virtualization, then it got to be 64-Bit.

You can use the following code to check whether the app is running as virtualized:

[DllImport("advapi32.dll", EntryPoint = "GetTokenInformation",
SetLastError = true)]
static extern bool GetTokenInformationNative(
IntPtr TokenHandle,
int TokenInformationClass,
ref int  TokenInformation,
int TokenInformationLength,
out int ReturnLength);

public bool IsVirtualized(IntPtr token)
    bool virtualized = false;
    int len = 4;
    int info = 0;
    if (!GetTokenInformationNative(token, 24, ref info, len, out
    len)) // 24 = TokenVirtualizationEnabled
       string s = "Win32 error " +
       throw new Exception(s);
    if(info != 0)
       virtualized = true;
    return virtualized;

// usage...

if(IsVirtualized(WindowsIdentity.GetCurrent().Toke  n))
// better add a manifest to your application if you end here ;-)

Thanks to Luc Pattyn[^] and Ajay Vijayvargiya[^] to point out the errors. :)


This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)


About the Author

You may also be interested in...


Comments and Discussions

GeneralMy vote of 3 Pin
i0013-Aug-17 13:28
member i0013-Aug-17 13:28 
GeneralReason for my vote of 5 You are right, I hadn't read with en... Pin
Sauro Viti21-Oct-10 20:32
memberSauro Viti21-Oct-10 20:32 
GeneralReason for my vote of 3 Good start, but some mistakes. Pin
Toli Cuturicu11-Oct-10 11:39
memberToli Cuturicu11-Oct-10 11:39 
GeneralIf using C++: IntPtr is not available in C++. Rather sizeof(... Pin
Ajay Vijayvargiya19-Sep-10 10:56
memberAjay Vijayvargiya19-Sep-10 10:56 

General General    News News    Suggestion Suggestion    Question Question    Bug Bug    Answer Answer    Joke Joke    Praise Praise    Rant Rant    Admin Admin   

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.

Permalink | Advertise | Privacy | Cookies | Terms of Use | Mobile
Web06-2016 | 2.8.180920.1 | Last Updated 21 Sep 2010
Article Copyright 2010 by GPUToaster™
Everything else Copyright © CodeProject, 1999-2018
Layout: fixed | fluid